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CIRCULAR 3 4 6, U. S. DEPARTMENT OF AGRICULTURE 



LACEWING FLIES 



The lacewing flies are delicate, four-winged insects, so named 

 because of the delicate tracery of their comparatively large, fragile 

 wings. Their larvae are long-bodied, thickest in the middle section 

 of the abdomen, and bear very long, sickle-shaped mandibles by means 

 of which they seize and drain the body contents of their prey. Be- 

 cause of these formidable mandibles and the aggressiveness of the 

 larvae in attack, they are often termed " aphis lions." There are 

 two groups of these insects, the green lacewing flies (family Chrysopi- 

 dae) and the brown lacewing flies (family Hemerobiidae). 



The green lacewing flies (species of Chrysopa and related genera) 

 (fig. 4) have the body and wings of a light greenish color and the 

 eyes brilliant gold. The larvae feed quite largely upon aphids, but 

 they may also attack thrips, jumping plant lice, mealybugs, scale 



Figure 4. 



-Chrj/xopa califormca Coq., a green lacewing fly ; A, Adult lacewing ; B, young 

 larva ; C, a group -of stalked eggs upon a leaf. A, X 2y 2 ; B, X 9. 



insects, red spiders, and the eggs of various insects. The eggs are 

 green, about one-thirtieth of an inch in length, and are usually de- 

 posited singly upon the foliage. They are placed at the end of slender 

 silken stalks one-fourth to one-half inch in length, an arrangement 

 which is said to protect them from various enemies. Some species 

 place the eggs in groups upon a single stalk or upon a bundle of fused 

 stalks. 



The larvae of many of the species of green lacewings have the 

 very interesting habit of covering their bodies with packets of trash 

 consisting of the shriveled bodies of aphids they have killed, molted 

 skins, and other material, this debris being loosely woven together 

 with silken strands. The body is often so completely covered by this 

 packet that it is not visible except while in motion, when what 

 appears to be a mere mass of trash proves to be the shelter borne 

 by the lacewing larva. 



